Method of making tin-based alloys for negative electrode compositions
View Patent ↗Powder milling techniques, tin-based alloys formed thereby, and the use of such alloys as electrode compositions for lithium ion batteries are provided. The alloys include tin and at least one transition metal but contain no silicon. The powder milling is done using low energy roller milling (pebble milling).
1. A method of making nanostructured alloy particles containing substantially no silicon, the method comprising: milling a millbase in a pebble mill containing milling media to provide the nanostructured alloy particles, wherein the millbase comprises: tin, carbon, and a transition metal selected from Fe, Ti, Y, V, Cu, Zr, Zn, Co, Mn, Mo, Ni, and Misch metal, and wherein the nanostructured alloy particles are substantially free of crystalline domains greater than 50 nanometers in size.
2. A method according to claim 1 , wherein the pebble mill has a theoretical critical speed, and the step of milling the millbase in a pebble mill comprises operating the pebble mill at a rotational speed in a range of from 50 to 140 percent of the theoretical critical speed.
3. A method according to claim 1 , wherein the pebble mill has a theoretical critical speed, and wherein the pebble mill has a containment wall having a temperature, and wherein the temperature is maintained at or below 100° C.
4. A method according to claim 1 , wherein the milling time is less than about 300 hours.
5. A method according to claim 4 , wherein the milling time is less than about 100 hours.
6. A method according to claim 1 , wherein the milling media comprises stainless steel.
7. A method according to claim 6 , wherein the media has an average diameter of less than about 1.3 cm.
8. A method according to claim 6 , wherein the media has an average diameter of less than about 0.70 cm.
9. A method according to claim 1 , wherein the millbase comprises at least one of iron or cobalt.
10. A method according to claim 1 , further comprising a milling aid.
11. A method according to claim 10 , wherein the milling aid comprises stearic acid.